Argent Vanguard Quests

I need some help here. So, for sometime now I have not been able to get my rep needed to get exalted for the Argent Crusade. This is because the quest line completely stopped working after a quest that involves you destroying 100 invaders and 3 dragons. After that, I could do one more quest and that was it. I'm sure this is a bug, but I would like some help because I've had a ticket up for the past two days and no one here to help me. I am on the Icecrown server if that has any help. If you know the answer, message me in-game or respond to this if i'm not in-game. Thanks.